Process for heat setting crimped synthetic polymeric fiber tow

ABSTRACT

An improved process is disclosed for the heating or heat treatment of a substrate, particularly a textile material in an oscillating electromagnetic field. The addition of ionic compounds to the material to be heated greatly enhances the heating or heat treatment of the material when subjected under proper moisture conditions to the effects of an oscillating electromagnetic field.

United States Patent 1191 Thrower, Jr.

[ PROCESS FOR HEAT SETTING CRIMPED SYNTHETIC POLYMERIC FIBER TOW [75]Inventor: Herbert T. Thrower, Jr.,

Spartanburg, 8.0.

[73] Assignee: Hystron Fibers Incorporated,

Spartanburg, SC.

[22] Filed: July 29, 1971, [21] Appl. No.: 167,156

[52] US. Cl. 117/931 DH, 57/157 TS, 34/1, 1l7/l38.8 F, 117/1395 CF,117/1395 co, 219/1061 51 111 ,01. B06111 1 1/11 1, H05b 9/00 [58] Fieldof Search. .ll 7/93 ,1 on, 139,511, 138.8 F, 117/1395 CF, 139.5WCQ;734/1; 162/192;219/10.61; 57/157 TS [56] References Cited UNITED STATESPATENTS 2,473,251 6/1949 Hsu l17/93.I DH

5 16 X Z 5 12 U) 0! L 8 CD I 1111 3,819,402 June 25, 1974 2,618,79611/1952 Brophy l17/93.1 DH 2,730,481 l/l956 Day 1l7/93.l DH 2,865,79012/1958 Baer 117/93,] DH

OTHER PUBLICATIONS Von Hippel, Dielectric Materials and Applications,John Wiley & Sons Inc., New York, p. 361, (1954).

Primary Examiner-William D. Martin Assistant Examiner-John H. NewsomeAttorney, Agent, or Firm-Wellington M. Manning, Jr.

[ 5 7] ABSTRACT 3 Claims, 1 Drawing Figure RELATIVE LOSS FACTOR OFFINISH, KIIX 1o" EFFECT OF LOSS FACTOR OF FINISH 0N HOT AIR SHRINKAGE OFFIBER HEAT-SET IN AN OSCILLATING ELECTROMAGNETIC FIELD PAIENIED 3. B 19,402

2 I6 g I2 U) g 8 1/ 3 RELATIVE LOSS FACTOR OF FINISH, KX IO EFFECT OFLOSS FACTOR OF FINISH ON HOT AIR SHRINKAGE OF FIBER HEAT-SET IN ANOSCILLATING ELECTROMAGNETIC FIELD INVENTOR. HERBERT T. THROWER,JR.

ATTORNEY BACKGROUND OF THE INVENTION The use of an oscillatingelectromagnetic field for the heat treatment of various and sundrymaterials has long been known. Depending upon the particular material orload being treated, numerous variations and modifications have been madeto the apparatus for creating the electromagnetic field, to the designof equipment for a particular application of the electromagnetic field,preconditioning of the material to be subjected to the electromagneticfield, and the like. Oscillating electromagnetic fields have beenemployed to dry paper, textiles, foods, and the like; to heat settextiles; to treat packaging materials; for moisture leveling; and otherwide and varied uses.

More particularly, the application of an oscillating electromagneticfield to the various products may involve an arrangement of apparatuswhereby opposite plates or grids are provided in parallel or angularrelationship with the load to be treated passing therebetween. Likewise,rods may be positioned in a side by side relationship with the materialpassing adjacent thereto or parallel rods may be deployed side by sideand apart from each other in opposite banks with the material passingtherebetween. Depending upon the particular product being subjected tothe effects of the field, one of the above referred to arrangementscould be employed.

Numerous variations have been made in the use of oscillatingelectromagnetic fields for the treating or drying of paper, textiles,food and the like. For example, substantial work has been conducted onthe particular arrangement of the field producing apparatus. Such workwas superficially mentioned above wherein opposite plates or grids, sideby side rods or opposite banks of side by side rods have been used.Additionally, it has been found by some that a particular end result maybe obtained by varying the attitude of the load (the material beingtreated) with respect to the electromagnetic field. As such, the loadcould be physically arranged to maintain a particular relationship tothe geometry of the electric field. Moreover, frequency variations havebeen found to be useful in drying where it has been stated that as themoisture content of the load becomes lower, the frequency should beincreased to continue to remove a desired amount of moisture. In certaincases, the oppositely positioned plates are angled in at one end, towardeach other whereby the voltage gradient increases with the decreasingspace between the plates. It has further been stated that certainconditioning of the load prior to exposure to the electromagnetic fieldwill achieve a certain end result.

Generally speaking, the prior art has been quite inconsistent in thetheoretical aspects of preconditioning of a substrate prior to passagethrough an oscillating electromagnetic field for the heating orotherwise treating of the substrate. For example, statements have beenmade in the prior art to the effect that the dielectric. constant of amaterial appliedto a load and subjected to an oscillatingelectromagnetic field is completely determinative of the improvedheating of the load in the field. Further. statements have been madethat relate a material having a high dielectric constant to also havinga high loss factor to thus improve drying, etc. of a load under theeffects of an oscillating electromagnetic field. Voltage variationacross the electrodes that are utilized to create the electromagneticfield has also been taught to afford improvement. Hence, as a mate- 5rial loses moisture, its power factor decreases thus necessitating ahigher voltage to maintain a relatively uniform effect on the material.Dipole moment of a material used to finish a textile substrate has alsobeen stressed as an important factor in improved effects on thesubstrate in oscillating electromagnetic fields. For example, one sourcestated that a material having a high dipole moment, such as water,experiences extreme molecular vibration in accord with the rapidlyreversing polarity of the electrodes, thereby creating increased heat onthe load.

All of the above statements prior to a vast amount of work that has beendone in the field of oscillating electromagnetic energy for industrialor other use. The present invention is still a further advance in thisparticular art, and teaches an improved process for the heating orotherwise heat treating of substrates, particularly textile materials bythe addition of certain ionic ingredients thereto.

While the prior art is quite sizeable and contains teachings pertinentto the heating of materials in an oscillating electromagnetic field,there is no teaching or suggestion in the prior art of the presentinvention. The prior art is exemplified by U.S. Pat. No. 2,390,572 toBrabander; U.S. Pat. No. 2,503,779 to Story; U.S. Pat. No. 2,530,680 toBurkholder; U.S. Pat. No. 2,709,856 to Hunter et al; U.S. Pat. No.3,205,334 to Manwaring; U.S. Pat. No. 3,292,270 to Spunt; U.S. Pat. No.3,399,460 to Russell; U.S. Pat. No. 3,435,534 to Knobloch et al; U.S.Pat. No. 3,484,179 to Adams et al; U.S. Pat. No. 3,485,984 to Ceruttiand U.S. Pat. No. 3,531,551 to McDonough and British patent 1,009,586 toL & L'Manufacturing, lnc.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide an improved process for the heating of textile materials in anoscillating electromagnetic field.

Another object of the present invention is to provide an improvedprocess for the heat setting of synthetic polymers under the effects ofan oscillating electromagnetic field.

Still another object of the present invention is to provide an improvedprocess for the heat treatment of a dielectric material in anoscillating electromagnetic field.

Another object of the present invention is to provide an improvedprocess for the heat treating of synthetic polymeric fibers in anoscillating electromagnetic field.

at least 4 per cent based on dry weight of the substrate.

Textile materials that may be treated by the process of the presentinvention include, but are not limited to filament, yarn, tow, staple,nonwoven, knit, woven, etc.

substrates. Furthermore, the textile material may be a natural material,a synthetic polymer or a combination of the two. Exemplary of suitablesynthetic polymeric materials that may also be treated according to thepresent invention are polyesters, polyamides, polyolefins,polyacrylonitriles and the like.

The process of the present invention may thus be utilized for theheating of textile materials either as piece goods or in a continuousmanner as in a process line. Furthermore, the process of the presentinvention is ideally suited for the heat setting of textile materialscontaining or consisting of high molecular weight syn- .thetic polymericmaterials such as polyester fibers or filaments. The process of thepresent invention is further suited for generating heat in a materialsuitable for the bonding of lamina to form a laminate; heat sealing ofplastics; for the application, drying, or curing of textile finishingcompositions, coatings, films and the like.

. Moreover, the process of the present invention may be controlled insuch a manner to heat a substrate without causing damage to thesubstrate and in particular to heat a textile material having aparticular finish thereon to remove a carrier from the finish withoutactivating other ingredients of the finish as might be required prior tocuring a textile resin, for example, for permanent press applications oreven curing the textile resin, if desired.

The present invention is thus directed to the addition of ionicmaterials in a carrier such as water to amaterial to be treated in anoscillating electromagnetic field. Ionic materials having a high lossfactor in the particular operating frequency improve heat conversion inthe electromagnetic field. These ionic materials may be cationic,anionic, or may be of an organic or inorganic nature.

The operating frequency range of the oscillating electromagnetic fieldcan be set as desired. It has been determined, however, that the processof the present invention performs best at lower frequencies.Accordingly, an operating frequency for the oscillating elec tromagneticfield is preferred in a range up to about 300 megahertz.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE is a graphical presentationof the effect of loss factor of a finish composition on residualshrinkage of a heat treated polyester fiber.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS The process of the presentinvention is suitable for the heating of numerous substrates,particularly textile substrates including both natural and synthetictextile materials. For example, cotton, wool and rayon exemplify naturaltextile materials. Polymers, copolymers, terpolymers, etc. containingpolyesters, polyamides, polyolefins, polyacrylonitriles, and the likeincluding the possible modifications thereto, typify synthetic polymersthat may be treated by the present process. Additionally, blends ofnatural and synthetic material may likewise be treated. Insofar as thetype of substrate, per se is concerned, the process of the presentinvention may be advantageously utilized for fibers, yarns, staple, tow,fabrics, garments, films, coatings, laminates and the like.

strued to include the removal of moisture from a load,

heat setting of the load or portions thereof, curing of a load or thelike. In fact, a preferred use of the process of the present inventionis to heat set wet crimped polyester fiber tow which is measured byresulting shrinkage of the fiber in hot air or water. As such, thepresent process willbe hereinafter described with relation to heatsetting of polyester filament tow, though the principals alluded toequally apply for conventional drying or other heat treatment of thematerials and substrates hereinbefore mentioned.

A finish containing a certain amount of the active ionic ingredient isapplied to the textile material, in this case, a polyester filament towwhich is to be heat set. Preferably, the finish composition will beapplied in an aqueous mixture though numerous other carriers or basesmay be utilized to obtain the same or similar results. The textilematerial having the particular improved finish thereon is passed throughan oscillating electromagnetic field under proper moisture conditionswhere improved heat setting of the polyester filaments takes place. Inthe sense of application of the finish to the substrate, in general, theionic constituent may be applied to the textile material at any pointprior to treatment in the oscillating electromagnetic field, providedthat, prior to treatment in said field, the substrate has a propermoisture content. Hence, the ionic compound may be applied in an aqueouscomposition, may be incorporated into the polymer, may be added in apaste, semi dry or dry state or the like. Thereafter, if the substratedoes not contain the proper moisture content, moisture must be added toachieve same. Likewise, the ionic constituent may be included in astretch finish bath or the like either alone or with other constituentsas might be desirable for a particular result.

Moisture conditions according to the teachings of the present inventionare an important variable in the process. A dry substrate, one having aninitial moisture content below about 4 per cent by weight, will notperform satisfactorily according to the teachings of the presentinvention. It is thus necessary to present the substrate to theelectromagnetic field, at a moisture content of at least about 4 percent by weight of the substrate. Preferably, the moisture content of thesubstrate should be at least about 7.5 per cent by weight of thesubstrate. Beyond about 20 per cent moisture based on the weight of thesubstrate, however, the improved effects became uneconomical due to thecost of moisture removal. As such, after application of the finish, themoisture content should preferably be con-' trolled in the range ofabout 4 to about 20 per cent based on the weight of the substrate. Thusliquid may be added to the substrate or expelled from the substrateprior to subjecting the substrate to the oscillating electromagneticfield. Moisture as referred to herein in-' cludes any liquid carrierthat is compatible with both the ionic compound and the substratewithout adverse effects thereto, and that can be removed by theelectromagnetic field. r

The ionic materials added to the substrate to bring about the improvedheating conditions according to the teachings of the present inventionshould yield a finish composition having a higher relative loss factorthan that of water. Much of the prior art refers to water as being thekey to success of electromagnetic fields with out any definition as tothe particular water being used. Demineralized water for example givesno effect whatsoever, though much of the prior art credits water as theactive component for improved heating. It can be hypothesized that thewater being used according to the prior art contained a certain ionconcentration such that some effect was obtained. Such is, however, farfrom a teaching of the present invention. Tap water varies considerablyfrom one area to another. Moreover, tap water in the same area will varyconsiderably in ion content at different times of the year. Hence whatmight improve the effects of an oscillating electromagnetic field at onetime of the year will have little or no effect at a different time ofthe year. The present invention has now precisely determined the activeingredients that improve the heating effects on a substrate in anoscillating electromagnetic field. With the teachings set forth herein,one can now completely and consistently control the improved heating torealize an anticipated result.

it has been determined that ionic materials having a high loss factor atthe operating frequency of an oscillating electromagnetic field improvethe heating effects of the field when added to a material beingsubjected to the field.

Theoretically, the heating in an oscillating electromagnetic field ispredicated upon the ability of the load to convert available electricalenergy into heat. Moreover, a load placed between the plates of a radiofrequency generator may be considered analogous to a capacitor andresistor in paralleL'Current flowing through the capacitor is consideredas charging current and current through the resistor is considered asloss current. The loss current is that portion that is converted intoheat. Total current flow in the field may thus be defined according toVon Hippel, Dielectric Materials and Applications, pp 3, 4. M.l.T. Press(1954), as

l total l charging l loss where:

1 total total electrical current through the electromagnetic field lcharging charging current component that leads by a temporal phase angleof 90 l loss loss current component in phase with voltage j= a complexalgebra vector operator w angular frequency of applied current Ccapacitance of the load C capacitance of free space G reciprocal of loadresistance V applied voltage e permittivity of the load e, permittivityof free space e'/e,, relative permittivity k v Total current flow maythus further be defined as 1 total jwk*C0V relative dielectric constante'/e tan 5 loss tangent or dissipation factor 1 loss loss currentcomponent in phase with voltage l total (/wk' w COV (8 Hence, comparingequations 3 and 8, it is seen that the product of the loss factor andthe frequency, called the dielectric conductivity, determines the amountof electrical energy that is transformed into heat. To increase theheating of a load under the effects of an electromagnetic fieldoperating at a set frequency, the loss factor associated with the loadshould thus be increased. Further, depending upon the magnitude of theoperating frequency, the loss factor of a material has been found to besubstantially independent of its dielectric constant.

Ionic finishes suitable for application to polyester filaments accordingto the teachings of the present invention may be anionic or cationic innature and further the ionic constituent may be an organic or inorganiccompound. Examples of suitable ionic compounds that may be added to thefiber finishes and applied to the filaments include, but are not limitedto, sodium nitrite, magnesium chloride, sodium sulphate, Parastat C-2, acationic diethyl sulfate imidazoline, produced by Trylon Chemical, lnc.,Mauldin, South Carolina and Tryfac 525K, an alkyl ethyoxy potassiumphosphate, produced by Trylon Chemical, Inc., Mauldin, South Carolina.Each of the compounds listed above, when added to polyester filaments inan aqueous finish composition, brought about a noticeably improvedheating of polyester filaments to the point of heat setting thepreviously crimped filaments. in addition to the ionic compounds appliedto the textile substrate, other ingredients may be simultaneouslyapplied therewith. For example, a normal finish for a syntheticpolymeric fiber or filament may include not only the ionic constituenttherein, but also dyestuffs, antistats, lubricants and other finishingcompounds such as textile resins and the like. Also, as mentioned above,while the composition is preferably an aqueous composition, other liquidcarriers may be employed.

The presence of the ionic compound in the finish improves the conversionof electrical energy into heat whereby the previously crimped filamentsare heat set. The degree of heat setting is evidenced by the per centfiber shrinkage in hot air at 392F. A low per cent shrinkage indicatesgood heat setting. It has been shown that an ionic material containingcomposition having a high relative loss factor measured at roomtemperature and a frequency of 15 megahertz will, when added to a load,improve the conversion of electrical energy into heat when the load ispassed through an oscillating electromagnetic field. The degree ofheating of the load may thus be empirically predicted by control of ionconcentration in the finish composition, operating frequency of theoscillating electromagnetic field, voltage gradient across the field andmoisture content of the load.

Though as mentioned above, a relative loss factor greater than watershows improvement, it is preferred according to the teachings of thepresent invention that the composition applied to the load have arelative loss factor of at least about 300 when measured at roomtemperature and 15 megahertz. A finish composition having a relativeloss factor of at least about 300 at the previously mentioned conditionsconverts sufficient electrical energy into heat to heat set thepreviously crimped polyester filaments. Temperatures significantlyhigher than 212F. are generally required for suitable heat setting ofpolyester filament tows, and though an aqueous finish composition hasbeen used predominantly, it is hypothesized that as water is evaporated,the concentration of ions increases to thus raise the boiling point ofthe remaining aqueous medium. As such, the higher heat settingtemperatures are reached in the field. It is not intended, however, thatthe present invention be limited to this theory.

Addition of ionic compoundstoa finish increases the electricalconductivity of the finish. Hence, sufficient ionic material should beadded to the finish to permit conductance of the electrical energy to beconverted into heat. There is not, however, a direct relationshipbetween finish conductivity and heat generation in the electromagneticfield. Instead, for each particular system, there is a level ofconductivity at which sufficient current may pass and beyond which,increases in conductivity though helpful, are not appreciably additivetowards further heat generating capability. Beyond about 0.4 millimhosper centimeter, for example, a higher ion concentration will notappreciably add to the heat generation capability in the electromagneticfield. Also, high conductivity in a finish having a low relative lossfactor will not perform satisfactorily according to the teachings of thepresent invention. riieo seiaiifigfreqtifieyafifi electromagnetfifild isa further important consideration. Improved effects due to the additionof ionic materials to the load should be noticed at any operatingfrequency. The greatest improvement has been noticed, however, in thelowerfrequency range of the spectrum. Hence, an electromagnetic fieldoscillating at a frequency of up to about 300 megahertz is preferred forpractice of the process of the present invention. A frequency range offrom about 0.1 to about 30 megahertz is further preferred. The lowerfrequency level is more economical and more effective during operation.

Voltage gradient across the electromagnetic field must also beconsidered for the process can be rendered unsuccessful by use of anincorrect voltage gradicut for the particular material being treated.Too high a voltage gradient or inadequate vapor removal capacity forexample, can cause arcing between the electrodes which will deactivatethe field producing generator. Hence, a proper voltage gradient for aparticular system (load and finish) should be that gradient as high aspossible without causing arcing across the electrodes. Such a conditioncannot be numerically expressed due to the large variance in materialsthat may be treated and ionic compounds being used. Likewise, there isgreat divergence in the expected end result. For the heat setting ofhigh molecular weight synthetic polymer fibers and filaments, a voltagegradient in the range of from about 0.2 to about 5.0 kilovolts percenti-' meter spacing between the electrodes is preferred.

Having discussed parameters of the present invention, the followingexamples are submitted to more fully describe the specifics of theinvention and to permit a better understanding thereof.

quency oven, Model HFV60, manufactured by Siemens, AG, Erlangen,Germany, and passed therethrough at a rate sufficient to permit aresidence time of 65 seconds in the oven. Plates in the oven were set ata gap of 13 centimeters at entrance and tapered to a 9 centimeter gap atexit. Applied voltage was 15,000 volts and operating frequency was 15megahertz. Measured current through the oven was 1.1 amps. The towentering the oven exhibited a moisture content of 6 per cent by weightand a fiber shrinkage of 22 per cent in hot air at 392F. Samples weretaken from the tow at the exit end of the oven and analyzed forshrinkage in hot air at 392F. Hot air shrinkage of the filament samplesaveraged 21.1 per cent. Hence, though some of the water may have beenremoved from the tow during passage of the tow through the oven, the towwas still moist to the touch and the 21.1 per cent shrinkage in hot airafter passage through the ovenindicated virtually no heat setting of thecrimped filaments. Data and results from Example I are reported in TableI.

" amnesia Example I was repeated under identical conditions except forfinish composition. In Examples 2-16, various organic and inorganicionic compounds were added to a finish which was applied to the towprior to stretching in steam. Data and results from Examples 2-16 areset forth below in Table I. 7 W

Normal shrinkage for this particular polyester fiber is in the range of20 to 22 per cent. From Table I, it can readily be seen that low fibershrinkage and thus good heat setting was achieved when certain ioniccompoundswere added to the finish. Note, however, although urea has ahigh dipole moment, it has a relatively low loss factor and thusperformed only slightly better than demineralized water. Also note thatarcing occurred when sodium acetate was added. The arcing was presumedto be due to rapid decomposition of the sodium acetate, yieldingconductive vapor betweenthe electrodes. Aluminum sulfate also showedonly a slight improvement over demineralized water. As can be seenbelow, both aluminum sulfate and urea solutions were analyzed to haverelatively low loss factors.

Results from Table 1 thus show ionic compounds, both organic andinorganic, as contributory to improved heat setting of polyester fibersunder the effects of an oscillating electromagnetic field. Low fibershrinkage as mentioned above, is evidence that the fiber underwentsufficient heating to set the molecular structure of the fibers in thecrimped state. An acceptable residual shrinkage for the particularpolyester fiber treated is in the neighborhood of 6 per cent or less.Hence, Examples 2l6 dramatically illustrate the improvement obtained byadding an ionic compound to a the finish. By so doing, the proper heatsetting may take place in the RP. oven and conventional drying can beavoided thereby. Stretch line speed can therefore be TABLE I EFFECTS OFIONIC FINISHES ON POLYETHYLENE TEREPHTHALATE FIBER SHRINKAGE EXAMPLEFINISH SPECIFICATION CURRENT FIBER SHRINKAGE NO. IN OVEN AFTER TREATMENTComponent Solids Conc. Conductivity millimhos/cm amps 1 Demineralized HO 0.0 0.003 1.1 21.1 2 Urea 0.39 0.0387 1.1 18.4 3 NaNo 0.044 1.347 1.58.9 4 do. 0.020 0.449 1.95 5 .3 5 do. 0.044 0.587 1.6 6.1 6 do. 01942.034 1.95 3.6 7 do. 0.44 4.738 1.8 3.1 8 NaAc 0.53 0.042 Arcing 18.3 9MgCl, 0.66 4.389 1.95 2.1 w mas n. 9-64 90.35 1-2 1 l Nil-2S0. 0.0460.542 1.9 5.6 12 Parastat C-2 3.2 0.570 1.9 3.2 13 do 1.0 1.211 1.75 5.914 Parastat C-2 1.0 0.287 1.8 6.2 15 Tryfac 525K 1 0 3.323 1.7 6.1 16Tryfac 525K 5 0 2.412 1.8 g 5.3

V 1 Fiber shrinkage measured in hot air at 392F. 2 Parastat C-Z is acationic diethyl sulfate imidazoline. Tryfac 525K is an anionic alkylpotassium phosphate. pH= 5.0

increased substantially over conventional dryers" and also over aconventional dryer in tandem with a radio frequency oven. Moreover,power consumption of the radio frequency oven is low compared toconventional heat setting of the polyester fibers.

EXAMPLE I? 4 dure was used to measure the dielectric properties of 5 thesolutions. Tabulated data and results of the analyses. are presented inTable II below. Also for comparative purposes, the fiber shrinkage datafrom Table l is reproduced beside the appropriate materials. 50

TAELE II A plot of relative loss factor for ionic compositions versusfiber shrinkage in hot air at 392F. is shown in FIG. 1. The solid linedrawn through the points clearly indicates a definite correlationbetween loss factor of the finish and heat effect on the fiber load.Hence, the experimental data of Table I is reinforced by the analyticaldata of Table II to definitely relate the loss factor of the finish atthe operating frequency to the heating effect on a load subjected to anoscillating electromagnetic field.

Having described the present invention in detail, it is obvious that oneskilled in the art will be able to make variations and modificationsthereto without departing from the scope of the invention. Accordingly,the scope of the present invention should be determined only by theclaims appended hereto.

What is claimed is:

1. An improved process for continuously heat setting high molecularweight synthetic polymeric fiber tow comprising the steps of:

a. applying a finish composition onto said tow, said finish compositionhaving a relative loss factor of at least about 300 when measured atroom temperature and 15 megahertz;

b. crimping said tow; and

RELATIVE LOSS FACTOR FOR SPIN FINISHES Fiber shrinkage measured in hotair at 392F. Parastat O2 is a cationic dicthyl sulfate imidazoline.l'ryfac 525K is an anionic alkyl potassium phosphate.

lar weight synthetic polymeric fiber tow as defined in claim 1 whereinthe tow is a polyester fiber tow.

3. The process as defined in claim 1 wherein the composition containsanionic constituent selected from the group consisting of sodiumnitrite, magnesium chloride, sodium sulfate, an alkyl sulfateimidazoline and an alkyl ethoxy potassium phosphate.

2. An improved process for heat setting high molecular weight syntheticpolymeric fiber tow as defined in claim 1 wherein the tow is a polyesterfiber tow.
 3. The process as defined in claim 1 wherein the compositioncontains an ionic constituent selected from the group consisting ofsodium nitrite, magnesium chloride, sodium sulfate, an alkyl sulfateimidazoline and an alkyl ethoxy potassium phosphate.